Computing devices with touch screens are capable of detecting objects in contact with the screen. Multi-touch displays are configured to sense and identify multiple contacts concurrently. Managing data about these contacts may be difficult for application programs executed on the computing devices. It may be difficult for an application program to ascertain a shape of a contact and to track changes in the shape of the contact over time. For example, if the contact is manipulated by a user, the contact location may change and the contact shape may change. As a result, the application program may consume significant processing resources acquiring and processing an image of the contact on the screen, and tracking changes to the image of the shape of the contact. For systems that track multiple contacts simultaneously, even greater processor resources can be consumed.
As a result of these challenges, developers may experience technical hurdles, delays, and cost overruns in developing application programs that are compatible with multi-touch screens, creating a barrier to market entry for new application programs. The quality and user experience of the resulting application programs may also vary. With such product development barriers, and potential varying quality of the resulting application programs, users may be reticent to adopt such touch screen devices in the future.